Retrofit Telestart T90 on T5GP ThermoTopC: recognized, but does not start

[enkor]

I will buy fob for testing as soon as I find it at a reasonable price.

I found somewhere that T91R is stripped of version to save production costs. And it only supports remote activation. But I lost the source of this information.

 

[enkor]

I have successfully started Webasto with esp32 using this ugly homemade circuit.

I used this interface GitHub - stuartpittaway/WebastoWBUSInterface: Hardware circuit diagram for interfacing to the Webasto WBUS interface from a PC/Arduino . It would be a lot of easier to use L9637D, but I had all the parts for the circuit at home.

Then I used code from this guy as a starting point.

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[eugene]

I have successfully started Webasto with esp32 using this ugly homemade circuit

View attachment 267075

Well done! What sw did you use? Does it emulate w-bus?

 

[enkor]

Well done! What sw did you use? Does it emulate w-bus?

There is no need for emulation. W-bus is standard k-line protocol. And with L9637D (or homemade) you can use it with arduino/esp32 (with additional level shifter) uart interface. So you are just sending/receiving messages over serial.

These guys reverse engineered the w-bus protocol and it is well documented W-Bus library and applications

I'm only sending message for turning webasto on and keeping it alive for specific time. I don't care about the readings from the heater.

I checked everything with oscilloscope before I plugged it in car.

Here is the code for platformio. I just renamed extension to txt instead of cpp.

 

[eugene]

There is no need for emulation. W-bus is standard k-line protocol. And with L9637D (or homemade) you can use it with arduino/esp32 (with additional level shifter) uart interface. So you are just sending/receiving messages over serial.

These guys reverse engineered the w-bus protocol and it is well documented W-Bus library and applications

I'm only sending message for turning webasto on and keeping it alive for specific time. I don't care about the readings from the heater.

I checked everything with oscilloscope before I plugged it in car.

Here is the code for platformio. I just renamed extension to txt instead of cpp.

Very nice (and cheap!!!)

Meanwhile, I have found that allegro has T90 receivers at very reasonable prices, around 30 eur (so you could order it there too if you needed).
So I ordered 4F0909509 (4F0909509A, 4F0909509B). This one doesn't have an R at the end so I assume it will allow analog pins.

What I was very suprised to find out was that VW OEM T90 reciever is compatible with non-VW Webasto egg-shaped remote!!!
This is actually very good news because you have more options to look for a better price.
Here's the kit I put together for VW T5 Multivan (remote and receiver linked successfully and working as intended):



I will test the analog pins later but I am pretty sure they work.

 

[enkor]

I bought FOB 7N0963511 out of curiosity. But I couldn't get it to work. Im able to pair the FOB with the Telestart (I can see its serial number in VCDS.) When I press the ON button then I can see in VCDS that the remote status changed from recognized to ON. It only lasts a few seconds, then it goes back to recognized and nothing happens.

I can see on scope that there is some outgoing communication from Telestart unit. But it seems that webasto is not accepting it, there is nothing shown on Thermotest in protocol.

Coding of webasto unit is 001031 (I changed it from 000031).

My device is still able to start webasto without any problems (I have unplugged it when I testing FOB)

What is wrong that when i press ON and OFF then I have no feedback about setup.

Does anybody encountered this problem ? I don't know what to do more.

 

[enkor]

After further research and reading the manual, it seems that I need to set it up before I can use it in the car roof display. Which is the problem because I have a secondary air heater and when I activate the remote option it is related to the air heater. Thus Im not able to set the settings for the webasto.

It seems that Telestart T91R needs to cooperate with other VW systems.